Sectional hot top



March 27, 1962 E. MARBURG SECTIONAL HOT TOP Filed Oct. 20, 1959 4Sheets-Sheet 1 vINVENTOR. 0644 M MMM JWORNEY E. MARBURG SECTIONAL HOTTOP March 27, 1962 4 Sheets-Sheet 2 Filed Oct. 20, 1959 March 27, 1962E. MARBURG 3,026,585

SECTIONAL -HOT TOP Q i l l l N Qi n N "IR INVENToR. W 20% ma@ 445026 NBY L* @mM/fw JNO/@yi Y March 27, 1962 E. MARBURG sEcTIoNAL HOT 'rop 4Sheets-Sheet 4 Filed 001;. 20, 1959 w @uw 3,026,585 SECTIONAL HUT TOPEdgar Marburg, Pittsburgh, Pa., assignor to United States SteelCorporation, a corporation of New Jersey Filed Oct. 20, 1959, Ser. No.847,599 Claims. (Ci. 22--147) This invention relates to a sectional hottop and more particularly to such a hot topi for use in a big-end-downingot mold of large size such as 22 x 35 inches. Hot tops most commonlyused for casting steel ingots are the one-piece variety. However, theyhave deiinite disadvantages, one of which is that they cannot closelyiit the walls of the ingot mold since the tolerance allowed in suchmolds is such that the hot top must be designed to clear scrap that mayadhere to the top of a mold of the minimum opening for a given size ofingot. The molds will generally be larger than this size. Because of thedisadvantages of a one-piece hot top sectional hot tops have beenproduced and have had limited use. However, the sectional hot tops ofwhich I have knowledge have proved unsatisfactory for various reasons.They may be difficult to manufacture and/or install, they may be weakstructurally, they may not conform suiciently close to the mold wall toprevent metal from getting therebetween, the vertical joints between theslabs of the hot top may not Vbe sufficiently tight to prevent metalleakage, the slabs of the hot top may not always be at the same levelwhen assembled in oversized molds, so that the volume of the sinkheadwill not contain adequate metal to insure a sound ingot, and the shapeof the opening formed by the hot top may not be the best for the mosteiieient utilization of the metal in the sinkhead. With all of the hottops of which I have knowledge the ingot weight will vary when the molddimensions vary from those specified.

It is therefore an object of my invention to provide a sectional hot topwith good structural strength which will closely contact all four wallsof the ingot mold.

Another object is to provide such a hot top which is readily installedin an ingot mold.

Still another object is to provide such a hot top which will eliminateor greatly reduce the iins on ingots and produce a sound ngot.

A further object is to provide such a hot top which will enable theingots to be so cast that they will be of approximately the same weighteven if the mold dimensions vary above those specified.

These and other objects will be more apparent after referring to thefollowing specification and attached drawings, in which:

FIGURE l is a plan view of an assembled hot top;

FIGURE 2 is an elevation showing the hot top assembled in an ingot mold;

FIGURE 3 is a view taken on the line III-III of FIG- URE l;

FIGURE 4 is a view taken on thetline IV-IV of FIG- URE 1;

FIGURE 5 is a view taken on the line V-V of FIG- UREI;

FIGURE 6 is a view taken on the line VI--VI of FIG- URE 1;

`FIGURE 7 is an enlarged view of the lower portion of FIGURE 6 showingthe relationship of the side and end slabs when inserted in a mold ofsmaller size (for example lt inch smaller) than the nominal standard;

FIGURE 8 is a view, similar to FIGURE 7, but with the slabs inserted ina mold of standard size;

FIGURE 9 is a view, similar to FIGURE 7, but with the slabsinserted in amold of larger size (for'example 1A inchv larger) than the nominalstandard; and

FIGURE l0 isv a view, similar to FIGURE 9, but with Patented Mar. 27,i962 the slabs inserted in a mold of still larger size (for ex ample 1/2inch langer) than the nominal standard.

Referring more particularly to the drawings, reference numeral 2indicates the top of a mold on which the hot top is positioned. The hottop consists of a pair of end slabs 4 and a pair of side slabs 6. Eachof the end slabs includes a generally vertical portion 8 and a generallyhorizontal portion It)` extending outwardly from the bottom of portion8. The outer face 12 of the portion It) is shaped to contact the moldwall with the bottom I4 thereof being tapered inwardly to provide forease of entrance into the mold. The portion 8 has a generally verticalgroove I6 in its inner face adjacent each end thereof. As shown inFIGURE 6 the bottom of the groove 1.6 extends downwardly from the top ofthe slab in a substantially vertical plane for the majority of itslength. It then tapers outwardly at 18 toward the inner face of theslab. I have found that the length of the portion 18 should preferablybe about six inches and its taper 1A; inch per inch. As shown in FIGURE3 the sides of the groove I6 slope downwardly toward the adjacent endface 20. Each of the end faces 2h preferably has a short verticalportion 22 at its top and a portion 24 adjacent thereto which tapersdownwardly toward the opposite face. A tapered portion 26 is provided atthe bottom for ease of insertion into the mold. Above portion 26 thereis a base portion 28 which is shaped to conform to the wall of the mold.A recessed portion 30 is provided between the portions 24 and 28 toallow clearance for any small pieces of slag or metal that may adhere tothe mold wall. As shown in FIG- URES l and 5 the outer face of each ofthe vertical portions 8 is provided with a pair of holes 32, forreceiving steel back-up rods 34 which extend outwardly beyond thehorizontal portion l0. The rods 34 may be embedded in the slab duringits manufacture. A vertical slot 36 extends upwardly from the bottom ofthe slab 4 and terminates short of the top thereof. An opening 38extends inwardly from the top of slot 36 to the inner face of the slab.An exothermic insert iti is provided in the slot 36 and opening 38. Theexothermic insert eil may be precast, in which case the refractory ofthe slab is formed therearound, or it may be placed in the slot duringor after formation of the slab in powdered form, and subsequently bakedto hardness at 300 to 400 F. for one or two hours. If desired theexothermic material need only be inserted at the bottom of slot 36 andin the opening 38 with a corrugated cardboard or other combustible llerpreferably being provided in the slot 36 between the exothermicmaterial. The slab is preferably made of sand with a resin binder. Insome instances the exothermic material may be omitted and the slab madesolid or with no exothermic material in the slot 36, in which casecorrugated cardboard might be provided in slot 36. Vent holes 42 extendoutwardly from the slot 36 to the outside face of the slab both toprovide air for combustion and to allow escape of gases from theexothermic material. Each of the -side slabs 6 is preferably thicker atits ends tf-t than at the middle portion as shown with its ends` 44being adapted to be received in the corresponding groove 16 in the endslabs. As shown in FIGURE 6 each end face of slab 6 extends downwardlyat 46 for the majority of its height and tapers slightly (1m inch)inwardly toward the opposite end face. Bottom 48 of the end face extendsat a greater taper (1/s inch per inch) toward the opposite lend face.The portion 48 has the same taper as portion V18 and is of less length.

hot top illustrated this width will be 16% inches, the same as the widthbetween end pieces, to provide maximum etliciency of shape. Each of theslabs 6 is provided with a vertical slot '50, opening 52, exothermicinsert 54 and vent holes 56 constructed in the same manner ascorresponding parts 36, 38, 40 and 42 of the end slabs. Notches 58 and60 may be provided in the middle of the top of slabs 4 and 6,respectively, to aid in assembling the slabs of the hot top in anapparatus for installing the hot top in the mold by crane.

in assembling the hot top in a mold the four slabs are arranged with theends 44 of the side slabs 6 in the grooves 16 of the end slabs 4, butwith the top of the side slabs some distance (about 6 inches) above thetop of the end slabs. When so positioned the slabs are lowered into theingot mold 2 until the tapered surfaces 24 of the end slabs 4 ibecometightly wedged between opposide sides of the mold wall. As the end slabs4 move downwardly to this position the rods 34 will be lowered insidethe mold in contact with the mold wall and will bend slightly, but willback up the slabs 4 to resist the outward pressure of the liquid metalin the hot top. The side slabs 6 are then forced downwardly in the slots16. As this occurs the taper in the sides of the grooves 16 directs thebottom of the side slabs 6 outward to near contact with the mold Wall.As may be seen in FIGURE 3 clearance is provided between the outsideface of the side slab and the upper portion of the mold wall for anydirt on the mold wall near the top thereof. As shown in FIGURE 6 thematching tapers 48 and 18 force the bottoms of the end slabs outwardlyinto contact with the mold wall. lf the mold is undersize, for example,1A of an inch, the end slab will tighten when the top of portion 48 isat or near the top of portion 18 as shown in FIGURE 7. When the mold isoversize, for example, it inch, the end slab will tighten when thebottom of the slabs are at the same height as shown in FIGURE 9. Whenthe mold is at the exact specified dimensions the bottom of the portion48 will be midway between the rst two positions as shown in FIGURE 8.When the mold is still further oversize (for example 1/2 inch) thebottom of the side slabs will drop below the bottom of the end slabs asshown in FIGURE 10. The close fit of the pieces with the mold wallsprevents metal tins on ingots. The taper of portion 46 provides forreduction of the overall length of the assembled hot top for ease ofinsertion in the mold and also enables insertion in undersize molds. Themold and hot top are now ready for pouring the molten metal into themold. It will be seen that the tapered portion 24 provides means forcompensating for variation in the width of the mold opening. Thus theWider the mold the further the slabs 4 go down into the mold. While thiscuts down the height of usable metal in the ingot the total volume ofusable metal will be approximately the same because the horizontalsection is greater. This is a deiinite advantage since it is desirableto have the Volume of metal in the ingot constant. As the metal ispoured into the mold the exposed faces of the exothermic material nearthe top are ignited by the heat from the pouring stream. The exothermicmaterial in the bottom of the slot will be ignited when the liquid metallevel approaches it. The material burns at about the rate of 1 inch perminute from each end to produce a temperature of 3000 to 3500u F. whichrapidly heats both the inside and outside sand walls. Since the sinkheadmetal is not directly in contact with the exothermic material except forsmall portions thereofV the metal will not be contaminated therewith.The inner sand walls `are made of such thickness that a metal shell ofsufficient thickness will solidify to enable the ingot to be lifted byits sinkhead. Once the shell has solidied the inner walls are extremelyhot and the temperature gradient across them is very low so that iteiectively restricts heat flow outwardly from the sinkhead. The

resin binder in the sand will volatilize from the heat of the pouredmetal so that the sand disintegrates readily about an hour after pouringand the stripped ingots are clean and substantially free from refractorycontaminants.

While one embodiment of my invention has been shown and described, itwill `be apparent that other adaptations and modifications may be madewithout departing from the scope of the following claims.

I claim:

1. A sectional hot top for a generally rectangular mold comprising afirst pair of slabs one located on each of two opposite sides of themold, a second pair of slabs one located on each of the other sides ofthe mold, each of the first pair of slabs including a generally verticalportion, the generally vertical portion having a generally verticalgroove in its inner face adjacent each end thereof, each of said grooveshaving a bottom and two sides, the bottom of each groove extendingdownwardly from the top of the slab in a substantially vertical planefor the majority of its length and then tapering toward the said innerface, the sides of each groove sloping downwardly toward the adjacentend face of its slab, the ends of each of said second pair of slabsbeing adapted to be received in the corresponding vertical groove of thefirst pair of slabs, the end face of each of said second pair of slabsextending downwardly for the majority of its length and then taperingtoward its opposite end face, the last named tapered portion having thesame slope as the tapered portion of the bottom of the groove in theassociated rrst pair of slabs but of less length than the taperedportion of the bottom of the groove whereby the hot top can be insertedin oversize and undersize molds.

2. A sectional hot top according to claim 1 in which each of said slabshas a generally vertical slot extending from the bottom thereof upwardlyless than the full height thereof and an inwardly extending opening fromthe top of said slot to the inner face of the slab, and exothermicmaterial in said slot and opening.

3. A sectional hot top for a generally rectangular mold comprising atrst pair of slabs one located on each of two opposite sides of themold, a second pair of slabs one located on each of the other sides ofthe mold, each of the trst pair of slabs including a generally verticalportion, the generally Vertical portion having a generally verticalgroove in its inner face adjacent each end thereof, each of said grooveshaving a bottom and two sides the bottom of each groove extendingdownwardly from the top of the slab in a substantially vertical planefor the majority of its length and then tapering toward the said innerface, each of the end faces of said rst pair of slabs having a portionadjacent its bottom adapted to contact the mold wall, a portion adjacentits top tapering downwardly toward the opposite end face and a recessedportion between the top and bottom portions, the sides of each groovesloping downwardly toward the adjacent end face of its slab, the ends ofeach of said second pair of slabs being adapted to be received in thecorresponding vertical groove of the rst pair of slabs, the end face ofeach of said second pair of slabs extending downwardly for the majorityof its length and then tapering toward its opposite end face, the lastnamed tapered portion having the same slope as the tapered portion ofthe bottom of the groove in the associated rst pair of slabs but of lesslength than the tapered portion of the bottom of the groove whereby thehot top can be inserted in oversize and undersize molds.

4. A sectional hot top for a generally rectangular mold comprising afirst pair of slabs one located on each of two opposite sides of themold, a second pair of slabs one located on each of the other sides ofthe mold, each of the first pair of slabs including a generally verticalportion and a generally horizontal portion extending outwardly from thebottom of the generally vertical portion, the generally vertical portionhaving a generally vertical groove in its inner face -adjacent each endthereof, each of said grooves having a bottom and two sides, the bottomof each groove extending downwardly from the top of the slab in asubstantially vertical plane for the majority of its length and thentapering toward the said inner face, the sides of said grooves slopingdownwardly toward the adjacent end face of its slab, the ends of each ofsaid second pair of slabs being adapted to be received in thecorresponding vertical groove of the iirst pair of slabs, the end faceof each of said second pair of slabs extending downwardly for themajority of its length and then tapering toward its opposite end face,the last named tapered portion having the same slope as the taperedportion of the bottom of the groove in the associated rst pair of slabsbut of less length than the tapered portion of the bottom of the groovewhereby the hot top can be inserted in oversize and undersize molds.

5. A sectional hot top for a generally rectangular mold comprising a rstpairof slabs one located on each of two opposite sides of the mold, asecond pair of slabs one located on each of the other Sides of the mold,each of the iirst pair of slabs including a generally vertical portionand -a generally horizontal portion extending outwardly from the bottomof the generally vertical portion, the generally vertical portion havinga generally vertical groove in its inner face adjacent each end thereof,each of said grooves having a bottom and two sides, the bottom of eachgroove extending downwardly from the top of the slab in -a substantiallyvertical plane for the majority of its length and then tapering towardthe said inner face, the sides of said grooves sloping downwardly towardthe adjacent end face of its associated slab, each of said end faceshaving a portion adjacent its bottom adapted to contact the mold wall, aportion adjacent its top tapering downwardly toward the opposite endface and a recessed portion between the top and bottom portions, theouter face of said vertical portion having a plurality of holes thereinabove the said horizontal portion, rods in at least part of said holesextending outwardly from said holes beyond the said horizontal portion,the ends of each of said second pair of slabs being adapted to bereceived in the corresponding vertical groove of the first pair ofslabs, the end face of each of said second pair of slabs extendingdownwardly and slightly toward the opposite end face for the majority ofits length and then at a greater taper toward its opposite end face, thelast named tapered portion having the same slope as the tapered portionof the bottom of the groove in the associated ''rst pair of slabs but ofless length than the tapered portion of the bottom of the groove wherebythe hot top can be inserted in oversize and undersize molds.

References Cited in the file of this patent UNITED STATES PATENTS2,049,980 Turner Aug. 4, 1936 2,159,374 Estep May 23, 1939 2,433,775Marburg Dec. 30, 1947 2,782,478 i Marburg Feb. 26, 1957 2,900,685Marburg Aug. 25, 1959 FOREIGN PATENTS 1,112,520 France Nov. 16, 19551,112,966 France 'Nov. 23, 1955

